experimentum crucis

What remained for me but to prove, by trial, that what might be perilous to other travellers was safe to me? The “experimentum crucis” was a visit to Al-Híjaz, at once the most difficult and the most dangerous point by which a European can enter Arabia.https://en.wikisource.org/wiki/Personal_Narrative_of_a_Pilgrimage_to_Al_Madinah_and_Meccah/Volume_I